The SeaMonkey project is a community effort to develop an all-in-one Internet application suite. It contains an Internet browser, email and newsgroup client with an included Web feed reader, HTML editor, IRC chat, and Web development tools, and is sure to appeal to advanced users, Web developers, and corporate users. It uses much of the Mozilla source code powering such successful siblings as Firefox, Thunderbird, Camino, Sunbird, and Miro.

BitlBee allows users to talk to people on the major instant messaging and microblogging networks (including MSN, Google Talk, AIM, and Twitter) from within any IRC client by emulating an IRC server. Virtual channels are created with all of the user's contacts in them, who can be talked to in the channel or in a query. Also, one can participate in group chats and chat rooms like they were normal IRC channels.

SILC (Secure Internet Live Conferencing) is a protocol which provides secure conferencing and chat services. It can be used to send any kind of messages, in addition to normal text messages, including multimedia messages like images, video, and audio stream. All messages in the SILC network are encrypted and authenticated, and messages can also be digitally signed. SILC protocol supports AES, SHA-1, SHA-2, PKCS#1, PKCS#3, X.509, OpenPGP, and is being developed in the IETF. The software is delivered as SILC Client for end users, SILC Server for system administrators, and SILC Toolkit for application developers.

Pidgin is a GTK2-based instant messenger application. It supports multiple protocols via modules, including AIM, ICQ, Yahoo!, MSN, Jabber, IRC, Napster, Gadu-Gadu and Zephyr. It has many common features found in other clients, as well as many unique features. Pidgin is not endorsed by or affiliated with AOL TimeWarner, Microsoft, or Yahoo.

Yate is a next-generation telephony engine. While currently focused on Voice over Internet Protocol (VoIP) and PSTN, its power lies in its ability to be easily extended. It supports SIP, H.323, IAX, MGCP, Jingle, Jabber, E1, T1, analogic, robbed bit, ISDN PRI, BRI, and SS7. YateClient is an Instant Messenger and Voice application for Jabber/Jingle IM, SIP, H.323, and IAX VoIP protocols.

Licq includes all the basic features of ICQ, like sending/receiving messages, chat, file transfer, contact list with pixmaps and user status, basic/extended user info, adding/editing users from within the GUI, user history, user groups, and new user registration. All commands and information are available through a simple and convenient tab dialog. Licq also has a completely configurable user interface with Skin and Icon pack support. It is written in C++ and comes with a GUI plugin using the Qt widget set. Other plugins are also available, like basic MSN support.

centericq is a text mode menu- and window-driven IM interface that
supports the ICQ2000, Yahoo!, AIM, IRC, MSN, Gadu-Gadu, and Jabber
protocols. It allows you to send, receive, and forward messages, URLs,
SMSes (both through the ICQ server and email gateways supported by
Mirabilis), contacts, and email express messages, and it has many other
useful features. An internal RSS reader and a LiveJournal client are
also provided.

Tsung is a distributed load testing tool. It is protocol-independent and can currently be used to stress HTTP, WebDAV, PostgreSQL, MySQL, LDAP, AMQP, and XMPP/Jabber servers. It simulates user behavior using an XML description file, reports many measurements in real time (statistics can be customized with transactions, and graphics generated using gnuplot). For HTTP, it supports 1.0 and 1.1, has a proxy mode to record sessions, supports GET, POST, PUT, and DELETE methods, cookies, and basic/digest authentication. It also has support for SSL, WebSocket, and BOSH.

Ekiga (formely known as GnomeMeeting) is a soft phone, video conferencing, and instant messenger application for use over the Internet. It supports HD sound quality and video up to DVD size and quality. It is interoperable with many other standards compliant software, hardware, and service providers as it uses both of the major telephony standards, SIP and H.323.

BZFlag is a 3D, multiplayer, tank battle zone,
capture the flag game that pits players against
each other in a networked environment. It runs on
Windows 95/98/NT/2000, Linux, MacOS 10.x, Irix,
Solaris, and others. An OpenGL accelerator is
highly recommended, but it is playable with 3D in
software.